Agree, power conditioner is a waste. Good UPC will detect problems and take your sensitive equipment off the line and give you time to power down properly, disconnect if necessary.
More importantly, have Whole Home Surge Protection installed at the Breaker Box (between the meter and your household main IIRC.
If the HDMI is a long run, as stated above, look at Ruipro (I think) hybrid optical cables. You may need an external power source rather than counting on the AVR to power the signal.
@TLS Guy is a great reference for this. I do not recall the thread in which he discussed this situation.